Branched-chain and Aromatic Amino Acids in Blood and Seminal Plasma are Associated with Sperm Parameters; A Practice within a Fertility Clinic Considering the Metabolic Syndrome.

The metabolomic approach has recently been used in the assessment of semen quality and male fertility. Additionally, the crucial roles of branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) in metabolic syndrome (MetS) were reported. However, little information exists about the association between BCAAs and AAAs with semen parameters, particularly in men with and without MetS. Our objective was to explore the association between BCAAs and AAAs in blood and seminal plasma and sperm parameters in men with MetS (MetS +) and without MetS (MetS-). In a cross-sectional study between January-July 2022, we investigated 98 men (age: 25-42 years; MetS + : n = 28 and MetS-: n = 70) at Royan Institute, Tehran, Iran. All participants underwent anthropometric indices measurements using standard protocols. From each participant, a single fasting blood sample was collected on the same day that the semen sample was collected. The BCAAs and AAAs in blood and seminal plasma were measured using high-performance liquid chromatography (HPLC). The aromatase activity (total testosterone/ estradiol ratio) was significantly lower in MetS + (0.16) than MetS- (0.35) (p = 0.016). Semen parameters were similar between the MetS + and the MetS- groups. All BCAA and AAA family members, except tryptophan, were higher in the blood plasma of men with metabolic syndrome. Meanwhile, the seminal plasma of BCAA and AAAs were similar. Intriguingly, Valine in blood (r = -0.329; p < 0.001) and seminal (r = -0.237; p < 0.05) plasma were correlated with abnormal sperm morphology in patients without metabolic syndrome (MetS-). Further research is necessary to validate these findings and to explore the underlying mechanisms and interactions between the plasma BCAAs and AAAs and sperm parameters.